Wireless control device

ABSTRACT

A wall-mountable wireless control device may include an antenna, a radio-frequency communication circuit, a control circuit, an enclosure, a conductive yoke, and/or a conductive member. The antenna may be configured to transmit and/or receive radio-frequency signals. The radio-frequency communication circuit may be configured to transmit and/or receive the radio-frequency signals via the antenna. The control circuit may be responsive to the radio-frequency communication circuit. The enclosure may be configured to house the radio-frequency communication circuit and the control circuit. The conductive yoke may be attached to the enclosure and configured to mount the control device to an electrical wallbox. The conductive member may extend around a rear side of the enclosure between opposite sides of the yoke.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of commonly-assigned U.S.Provisional Application No. 62/076,786, filed Nov. 7, 2014, andcommonly-assigned U.S. Provisional Application No. 62/005,424, filed May30, 2014, each entitled “Wireless Control Device”.

BACKGROUND

Home automation systems, which have become increasing popular, may beused by homeowners to integrate and control multiple electrical and/orelectronic devices in their house. For example, a homeowner may connectappliances, lights, blinds, thermostats, cable or satellite boxes,security systems, telecommunication systems, or the like to each othervia a wireless network. The homeowner may control these devices using acontroller or user interface provided via a phone, a tablet, a computer,and the like directly connected to the network or remotely connected viathe Internet. These devices may communicate with each other and thecontroller to, for example, improve their efficiency, their convenience,and/or their usability.

A wall-mounted load control device may be adapted to be mounted in astandard electrical wallbox. For example, a wall-mounted dimmer switchmay be coupled in series electrical connection between analternating-current (AC) power source and an electrical load (e.g., alighting load) for controlling the power delivered from the AC powersource to the lighting load and thus the intensity of the lighting load.Many prior art wall-mounted load control devices are capable oftransmitting and/or receiving wireless signals (e.g., radio-frequency(RF) signals) with other control devices in a load control system. Forexample, a wireless load control device may be configured to receivedigital messages via the RF signals for controlling the electrical loadand to transmit digital messages including feedback informationregarding the status of the load control device and/or the electricalload. Such wall-mounted wireless load control devices have includedantennas for transmitting and/or receiving the RF signals. Examples ofantennas for prior-art wall-mounted load control devices are describedin commonly-assigned U.S. Pat. No. 5,982,103, issued Nov. 9, 1999, andU.S. Pat. No. 7,362,285, issued Apr. 22, 2008, both entitled COMPACTRADIO FREQUENCY TRANSMITTING AND RECEIVING ANTENNA AND CONTROL DEVICEEMPLOYING SAME, the entire disclosures of which are hereby incorporatedby reference.

The components and/or building structure surrounding the location atwhich a wall-mounted wireless load control device is installed mayaffect the communication range (e.g., the transmission and/or receptionrange) of the control device. For example, the control device may bemounted in an electrical wallbox, and the electrical wallbox may be madeof a conductive material (e.g., a metal) or a non-conductive material(e.g., a plastic). In addition, a faceplate may be mounted to the loadcontrol device, and a part or the entirety of the faceplate may be madeof a conductive material (e.g., a metal) or a non-conductive material(e.g., a plastic). When the wall-mounted wireless load control device isinstalled in a metal wallbox or with a faceplate assembly made of metal,electric fields that are produced when the antenna is transmitting an RFsignal may cause current to flow through the metal wallbox and/orthrough the metal faceplate assembly, which in turn may affect thetransmission and/or reception range of the antenna.

The possible differences in the materials surrounding the installationlocation of the wall-mounted wireless load control device may cause thecommunication range of the load control device to vary from oneinstallation to another. However, it is desirable to have a consistentcommunication range and performance of the wall-mounted wireless loadcontrol device from one installation location to the next.

In addition, if the faceplate assembly mounted to the wireless loadcontrol device includes a large amount of metallization on the front (orouter) surface of the faceplate, the communication range of the wirelessload control device may be diminished to a point that the wireless loadcontrol device may not able to communicate with the other RF-enabledcomponents of the load control system. Since conductive faceplatestypically provide an attractive aesthetic appearance, it is desirable toinstall conductive faceplates on wall-mounted wireless load controldevices. Therefore, there is a need for a wall-mounted wireless loadcontrol device that is able to operate properly while installed with aconductive faceplate.

SUMMARY

As described herein, a wall-mountable wireless control device mayinclude an antenna, a radio-frequency communication circuit, a controlcircuit, an enclosure, a conductive yoke, and/or a conductive member.The antenna may be configured to transmit and/or receive radio-frequencysignals. The radio-frequency communication circuit may be configured totransmit and/or receive the radio-frequency signals via the antenna. Thecontrol circuit may be responsive to the radio-frequency communicationcircuit. The enclosure may be configured to house the radio-frequencycommunication circuit and the control circuit. The conductive yoke maybe attached to the enclosure and configured to mount the control deviceto an electrical wallbox. The conductive member may extend around a rearside of the enclosure between opposite sides of the yoke.

The wireless control device may include a user interface and/or afaceplate. The user interface may be configured to receive a user input.The faceplate may define an elongated opening for receiving the userinterface. The faceplate may comprise a conductive element electricallycoupled to the yoke via a single electrical connection when thefaceplate is installed on the wireless control device and the userinterface is received through the elongated opening of the faceplate.The conductive element may define a first slot that is substantially thesame size as and substantially aligned with the opening of thefaceplate. The conductive element may be configured to operate as aradiating element of the antenna when the faceplate is installed on thewireless control device.

The wireless control device may include a bezel attached to the yoke.The bezel may be configured to provide the user interface through theopening of the faceplate when the faceplate is installed on the wirelesscontrol device. The antenna may comprise a driven element locatedbetween the bezel and the yoke. The driven element may be capacitivelycoupled to the conductive element when the faceplate is installed on thewireless control device. The driven element may define a second slotthat is substantially the same size as and substantially aligned withthe opening of the faceplate when the faceplate is installed on thewireless control device.

The radio-frequency communication circuit may be electrically coupled tothe driven element via two drive points located on opposite sides of thesecond slot at approximately the middle of the second slot. Theconductive member may be electrically coupled to the opposite sides ofthe yoke adjacent the drive points of the driven element. The conductiveelement may be attached to a rear surface of the faceplate. Thefaceplate may have a conductive material on the front surface of thefaceplate. The conductive element may comprise a conductive material onthe front surface of the faceplate. The conductive element may belocated inside of the faceplate. The conductive element may beelectrically coupled to the yoke via one of a plurality of screws thatattach the bezel to the yoke when the faceplate is installed on thewireless control device. The conductive element may be configured tooperate as a patch antenna when the faceplate is installed on thewireless control device. The antenna may comprise a slot antenna or ahybrid slot-patch antenna. The conductive member may extend horizontallyaround the rear surface of the enclosure at the center of the yoke. Theconductive member may comprise a conductive strap, a conductive label,and/or a conductive paint. The conductive member may be a part of theenclosure. The enclosure may be made of a material that is conductive.The conductive member may be directly electrically coupled to theopposites sides of the yoke. The conductive member may be capacitivelycoupled to the opposites sides of the yoke.

Other features and advantages of the present disclosure will becomeapparent from the following description that refers to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an example wall-mounted load controldevice (e.g., a dimmer switch) having a thin touch sensitive actuator.

FIG. 2 is a front view of the load control device of FIG. 1.

FIG. 3 is a right side cross-sectional view of the load control deviceof FIG. 1 taken through the center of the load control device as shownin FIG. 2.

FIG. 4 is a top side cross-sectional view of the load control device ofFIG. 1 taken through the center of the load control device as shown inFIG. 2.

FIG. 5 is a partial exploded view of the load control device of FIG. 1showing a faceplate and an adapter plate removed from the load controldevice.

FIG. 6 is a rear perspective view of the faceplate of FIG. 5.

FIG. 7 is an exploded view of the load control device of FIG. 1 showinga portion of an antenna of the load control device.

FIG. 8 is a perspective view of another example wall-mounted loadcontrol device having a thin touch sensitive actuator.

FIG. 9 is a rear perspective view an example conductive faceplate (e.g.,a metal faceplate) that may be installed on the load control device ofFIG. 1.

FIG. 10A is a front view of the conductive faceplate of FIG. 9.

FIG. 10B is a front view of a driven element of the antenna of the loadcontrol device of FIG. 1.

FIG. 10C is a front view of the conductive faceplate of FIG. 10A and thedriven element of FIG. 10B overlaid overtop of each other.

FIG. 11 is a partial right side cross-sectional view of the conductivefaceplate of FIG. 9.

FIG. 12 is an enlarged perspective view of a conductive spring elementof the conductive faceplate of FIG. 9.

FIG. 13 is an enlarged partial top side cross-section view of the loadcontrol device of FIG. 1 with the conductive faceplate of FIG. 9installed on the load control device.

FIG. 14 is a simplified equivalent schematic diagram of the antenna ofthe load control device of FIG. 1 when no faceplate and/or a plasticfaceplate (e.g., a 100% plastic faceplate) is installed on the loadcontrol device.

FIG. 15 is a simplified equivalent schematic diagram of the antenna ofthe load control device of FIG. 1 when a conductive faceplate isinstalled on the load control device.

FIG. 16 is a perspective view of an example multi-gang installationhaving multiple load control devices with thin touch sensitiveactuators.

FIG. 17 is a front view of a multi-gang conductive faceplate of themulti-gang installation of FIG. 16 overlaid overtop of driven elementsof antennas of the load control devices.

FIG. 18 is a front view of an alternate multi-gang conductive faceplateoverlaid overtop of driven elements of antennas of the load controldevices of FIG. 16.

FIG. 19 is a rear perspective view of an example faceplate that may beinstalled on the load control device of FIG. 1, where the faceplate hasa conductive backer attached to a rear surface of the faceplate.

FIG. 20 is a partial exploded view of the load control device of FIG. 1showing the faceplate of FIG. 19 removed from the load control device,and the conductive element removed from the faceplate.

FIG. 21 is a right side cross-sectional view of the load control deviceof FIG. 1 taken through the center of the load control device as shownin FIG. 2 with the conductive element attached to the faceplate of FIG.19.

FIG. 22 is a top side cross-sectional view of the load control device ofFIG. 1 taken through the center of the load control device as shown inFIG. 2 with the conductive element attached to the faceplate of FIG. 19.

FIG. 23 is an enlarged partial top side cross-sectional view of the loadcontrol device of FIG. 1 taken through the center of the load controldevice as shown in FIG. 2 with the conductive element attached to thefaceplate of FIG. 19.

FIG. 24A is a front view of the conductive element of FIG. 19.

FIG. 24B is a front view of a driven element of the antenna of the loadcontrol device of FIG. 1.

FIG. 24C is a front view of the faceplate of FIG. 19, the conductiveelement of FIG. 24A, and the driven element of FIG. 24B overlaid overtopof each other.

FIG. 25 is a simplified equivalent schematic diagram of the antenna ofthe load control device when the faceplate of FIG. 19 with theconductive element is installed on the load control device.

FIG. 26 is a rear perspective view another example conductive faceplatethat may be installed on the load control device of FIG. 1, where theconductive faceplate has a conductive backer attached to a rear surfaceof the faceplate.

FIG. 27A is a front view of the conductive faceplate and the conductiveelement of FIG. 26.

FIG. 27B is a front view of a driven element of the antenna of the loadcontrol device of FIG. 1.

FIG. 27C is a front view of the conductive faceplate and the conductiveelement of FIG. 27A and the driven element of FIG. 27B overlaid overtopof each other.

FIG. 28 is a simplified equivalent schematic diagram of the antenna ofthe load control device when the conductive faceplate of FIG. 26 withthe conductive element is installed on the load control device.

FIG. 29 is a perspective view of an example wireless control device.

FIG. 30 is a simplified block diagram of an example load control device.

FIG. 31 is a simple diagram of an example load control system.

DETAILED DESCRIPTION

FIG. 1 is a perspective view and FIG. 2 is a front view of an examplewall-mounted load control device 100 (e.g., a dimmer switch). The loadcontrol device 100 may be used for controlling the power delivered froman alternating-current (AC) source to an electrical load (e.g., alighting load). FIG. 3 is a right side cross-sectional view of the loadcontrol device 100 taken through the center of the load control deviceas shown in FIG. 2. FIG. 4 is a top side cross-sectional view of theload control device 100 taken through the center of the load controldevice as shown in FIG. 2. FIG. 5 is a partial exploded view of the loadcontrol device 100 showing a faceplate 102 and an adapter plate 104removed from the load control device. FIG. 6 is a rear perspective viewof the faceplate 102. FIG. 7 is an exploded view of the load controldevice 100 showing a portion of an antenna of the load control device.

The load control device 100 may include a touch sensitive actuator 110.The touch sensitive actuator may be horizontally oriented along alongitudinal axis of the load control device 100. The faceplate 102 mayhave a body portion 105. The body portion 105 may define a front surface107 of the faceplate 102. The faceplate 102 may include a non-standardopening 106 in the front surface 107 of the body portion 105. Theopening 106 may be adapted to receive the touch sensitive actuator 110,for example, when the faceplate 102 is installed on the load controldevice 100. The opening 106 may have a length L_(OPENING). The openingmay have a width W_(OPENING). The opening 106 may have an aspect ratio(e.g., L_(OPENING):W_(OPENING)) of approximately 16:1. For example, thelength L_(OPENING) may be approximately 2.83 inches and the widthW_(OPENING) may be approximately 0.17 inches. The body portion 105 ofthe faceplate 102 may be made from, for example, a non-conductivematerial, such as plastic. The body portion 105 of the faceplate 102 maybe made from a conductive material, such as metal, for example. The bodyportion may be made of a non-conductive material and the front surface107 may include a conductive material (e.g., a metallic material), forexample as described herein.

The touch sensitive actuator 110 may include an actuation member 112.The actuation member 112 may include first and second portions 112A,112B. The load control device 100 may include a bezel 114. The bezel 114may be shaped to form an opening 113. The actuation member 112 mayextend through the opening 113 in the bezel 114 to contact a touchsensitive device 130 (e.g., a resistive touch pad) inside the loadcontrol device 100. The touch sensitive device 130 may be referred to asa user interface that a user may interact with, for example, in order tocontrol a lighting load. The load control device 100 may be operable tocontrol the intensity of the controlled lighting load in response toactuations of the actuation member 112 and/or the touch sensitive device130. The bezel 114 may include a break 116 that may separate the upperportion 112A and the lower portion 112B of the actuation member 112. Theload control device 100 may be configured to toggle a connected lightingload from on to off and vice versa, for example, upon actuation of thelower portion 112B of the actuation member 112. The load control device100 may be configured to adjust an intensity of the lighting load, forexample, based on actuation(s) of the upper portion 112A of theactuation member 112. The load control device 100 may adjust theintensity of the lighting load to a particular level based on theposition of the actuation along the length of the actuation member 112.

The load control device 100 may include a yoke 120. The yoke 120 may beused to mount the load control device 100 to a standard electricalwallbox, for example, via mounting screws (not shown) that may bereceived through two mounting holes 122. The yoke 120 may be made from aconductive material. The faceplate 102 may be mounted (e.g., snapped) tothe adapter plate 104, for example, such that the bezel 114 is housedbehind the faceplate 102 and the bezel 114 extends through the opening106. For example, tabs 108 on the top and bottom sides of the faceplate102 may be adapted to snap to tabs 109 on the top and bottom edges ofthe adapter plate 104. The adapter plate 104 may connect to the yoke 120of the load control device 100, for example, via faceplate screws (notshown) that may be received through openings 124 in the adapter plate104 and corresponding openings 125 in the yoke 120. The load controldevice 100 may include an enclosure 126 (e.g., a back box). Theenclosure 126 may house a rear printed circuit board (PCB) 128. Aportion of the electrical circuitry of the load control device 100 maybe mounted on the rear PCB 128. An air-gap actuator 129 may allow foractuation of an internal air-gap switch (not shown) to electricallydisconnect the electrical load from the AC power source, for example, bypulling the air-gap actuator down.

The load control device 100 may include a non-conductive cradle 132. Thecradle 132 may be shaped to form a recess 134. The recess 134 may beused to hold the touch sensitive device 130. The touch sensitive device130 may be electrically coupled to a front printed circuit board (PCB)136, for example, via connector pins 138 that may be received inthrough-holes 139 in the front PCB 136. The bezel 114 may attach to theyoke 120, for example, such that the cradle 132 and the front PCB 136are positioned (e.g., captured) between the bezel 114 and the yoke 120.For example, the bezel 114 may attach to the cradle 132 via screws 140(e.g., electrically conductive screws) that may be received throughopenings 141 in the bezel 114 and corresponding openings 142 in the yoke120. The air-gap actuator 129 may be positioned between the cradle andthe yoke 120 and is configured to actuate the internal air-gap switchinside of the enclosure 126 through a central opening 144 in the yoke120. The air-gap switch actuator 129 may be configured to translatealong the longitudinal axis of the load control device 100 to open andclose the internal air-gap switch. The front PCB 136 may be connected tothe rear PCB 128, for example, via two electrical connectors 145 thatmay extend through openings 147 in the cradle 132.

The actuation member 112 may be positioned (e.g., captured) between thebezel 114 and the touch sensitive device 130, for example, in the recess134 of the cradle 132, such that the front surface of the actuationmember 112 may extend through the opening 113 in the bezel 114. Theactuation member 112 may include actuation posts 146 that may contactthe front surface of the touch sensitive device 130. The posts 146 maybe arranged in a linear array along the length of the actuation member(e.g., along the longitudinal axis of the load control device 100). Theactuation posts 146 may act as force concentrators to concentrate theforce from an actuation of the front surface of the actuation member 112to the touch sensitive device 130. The front PCB 136 may be shaped toform holes 148. The actuation posts 146 may extend through the holes 148in the front PCB 136 to contact the touch sensitive device 130. Anexample of a load control device having a thin touch sensitive actuatoris described in greater detail in commonly-assigned U.S. Pat. No.7,791,595, issued Sep. 7, 2010, entitled TOUCH SCREEN ASSEMBLY FOR ALIGHTING CONTROL, the entire disclosure of which is hereby incorporatedby reference.

The front PCB 136 may include visual indicators, for example,light-emitting diodes (LEDs) 149, that may be arranged in a linear arrayadjacent to a rear surface of the actuation member 112. The actuationmember 112 may be substantially transparent, for example, such that theLEDs 149 are operable to illuminate portions of the front surface of theactuation member 112. Two different color LEDs 149 may be positionedbehind the lower portion 112B of the actuator member 112. For example,the lower portion 112B may be illuminated with blue light when thelighting load is on and the lower portion 112B may be illuminated withorange light when the lighting load is off. The LEDs 149 behind theupper portion 112A of the actuation member 112 may be blue and may beilluminated, for example, as a bar graph to display the intensity of thelighting load when the lighting load is on. The operation of the LEDs149 is described in greater detail in U.S. Pat. No. 7,592,925, issuedSep. 22, 2009, entitled LIGHTING CONTROL HAVING AN IDLE STATE WITHWAKE-UP UPON ACTUATION, the entire disclosure of which is herebyincorporated by reference.

The load control device 100 may include an antenna (e.g., a slotantenna). The antenna may comprise a driven element 150, and forexample, may be said to include one or more other elements. For example,the antenna may comprise any combination of the driven element 150, aconductive member (e.g., a conductive member 170), the yoke 120, one ormore conductive elements (e.g., a conductive faceplate and/or aconductive backer, as described herein), and/or the like. The antennamay include a wireless communication circuit 160. The driven element 150may be coupled to the wireless communication circuit 160. For example,the wireless communication circuit 160 may drive the driven element 150of the antenna. The wireless communication circuit 160 may be used fortransmitting and/or receiving radio-frequency (RF) signals, for example,via the antenna. The wireless communication circuit 160 may communicateRF signals at a communication frequency f_(RF) (e.g., approximately 434MHz). For example, the wireless communication circuit 160 may include anRF receiver, an RF transmitter, and/or an RF transceiver. The wirelesscommunication circuit 160 may be mounted to the rear PCB 128 inside theenclosure 126.

The driven element 150 may be formed of a conductive material (e.g., anelectrically-conductive material). The driven element 150 may besubstantially planar. For example, the drive element 150 may besubstantially planar except for feet 155, for example, as shown in FIG.7. The driven element 150 may be located between the bezel 114 and thefront PCB 136. The drive element 150 may be adapted to be attached to arear surface of the bezel 114. For example, the drive element 150 may beprinted or painted on the rear surface of the bezel 114. The drivenelement 150 may be a conductive label that is adheres to the rearsurface of the bezel 114. The driven element 150 may include a main slot152. The main slot 152 may extend along the longitudinal axis of theload control device 100. The main slot 152 may be approximately the samesize as the opening 118 in the faceplate 102 through which the bezel 114extends. When the faceplate 102 is connected to the load control device100, the main slot 152 is aligned with the opening 118 of the faceplate102. The actuation posts 146 of the actuation member 112 extend throughthe main slot 152 to the touch sensitive device 130. The driven element150 may form openings 154. The screws 140 that attach the bezel 114 tothe yoke 120 may extend through the openings 154, such that the screws140 may not be electrically coupled to the driven element 150.

The driven element 150 may include the feet 155 (e.g., drive points)that may be electrically connected to pads 156 on the front PCB 136 toallow for electrical connection to the wireless communication circuit160 on the rear PCB 128 through the connectors 145. The feet 155 may belocated on opposite sides of the main slot 152. The feet 155 may belocated at approximately the middle of the main slot, as exemplified inFIG. 7. The wireless communication circuit 160 may be configured todrive the feet 154 differentially, such that the driven element 150operates as a slot antenna and radiates the RF signals. The drivenelement 150 may operate as a radiating element of the load controldevice 100.

One or more elements of the antenna may act as a radiating element ofthe antenna. A radiating element may be any element that radiates asignal (e.g., a RF signal). For example, one or more of the drivenelement 150, the conductive member (e.g., a conductive member 170), theyoke 120, and/or one or more of the conductive elements (e.g., theconductive faceplate and/or the conductive backer) may act as aradiating element of the antenna. One of the radiating elements may bereferred to as an outer-most radiating element. The outer-most radiatingelement may be the structure that interfaces with the broadcastingmedium (e.g., ambient air, for example, the air that is immediatelysurrounding the load control device 100). For example, the drivenelement 150 and/or one of the conductive elements (e.g., the conductivefaceplate and/or the conductive backer) may operate as the outer-mostradiating element. The driven element 150 may operate as the outer-mostradiating element of the load control device 100 when, for example, thefaceplate 102 is not installed on the load control device 100 or anon-conductive (e.g., 100% plastic) faceplate is installed on the loadcontrol device 100.

The length and/or width of the main slot 152 of the driven element 150may determine the inductance of the driven element 150. The resonantfrequency of the antenna may be a function of the inductance of thedriven elements 150. The resonant frequency of the antenna may be afunction of the dimensions (e.g., length and/or width) of the main slot152. A communication range (e.g., a transmission range and/or receptionrange) of the antenna at the communication frequency f_(RF) of thewireless communication circuit 160 may depend on the length and/or widthof the main slot 152. The overall size of the driven element 150 and thedimension of the main slot 152 may be limited by the size of themechanical structures of the load control device 100 (e.g., the bezel114). At some communication frequencies (e.g., around 434 MHz), thedesired length of the main slot 152 to maximize the communication rangeof the antenna may be longer than length of bezel 114. The drivenelement 150 may include wrap-around slot portions 158 to increase theinductance of the driven element 150. The wrap-around portions 158 mayextend from the ends of the main slot 152. The wrap-around portions 158may be oriented substantially parallel to the main slot 152. The lengthof the main slot 152 and the wrap-around slot portions 158 may dependupon the communication frequency f_(RF) of the wireless communicationcircuit 160. The wrap-around slot portion 158 may be formed of othershapes, such as, for example, spiral shapes.

At higher communication frequencies (e.g., around 2.4 GHz), the desiredlength of the main slot 152 to maximize the communication range of theantenna may be shorter. Accordingly, the driven element 150 may notinclude the wrap-around slot portions 158. The length of the main slot152 may be shortened. The antenna of the load control device 100 mayinclude a dual resonant structure having two resonant frequencies, suchthat the load control device 100 is able to communicate at two differentcommunication frequencies (e.g., approximately 434 MHz and 868 MHz).

The load control device 100 may be mounted to a metal and/or plasticwallbox. One or more components of the faceplate assembly (e.g., thefaceplate 102 and/or the adapter plate 104) may be made of a conductivematerial (e.g., a metal) and/or a non-conductive material (e.g.,plastic). The load control device 100 may be configured such that animpedance of the antenna, and the communication range (e.g., atransmission and/or reception range) of the antenna at the communicationfrequency f_(RF) may be substantially consistent over variousinstallation conditions. The antenna may cause an electric field to begenerated, for example, when the antenna is transmitting. When the loadcontrol device 100 is installed in a metal wallbox, the electric fieldmay cause current to flow through the metal wallbox and affect thecommunication range of the antenna at the communication frequencyf_(RF).

The load control device 100 may include a conductive member 170. Theconductive member 170 may be a conductive label, such as a metal label.The conductive member 170 may wrap around the back of the enclosure 126between points on opposite sides 121 of the yoke 120. For example, theconductive member 170 may wrap around the back of the enclosure 126between opposites sides of the central opening 143 and adjacent the feet155 of the driven element 150. In other words, the conductive member 170may extend horizontally around the back of the enclosure 126 at thecenter of the yoke 120. The conductive member 170 may be directlyconnected or capacitively coupled to the opposite sides 121 of the yoke120. For example, the conductive member 170 may be screwed to the yoke120 via one or more conductive screws. The conductive member 170 mayinclude a conductive coating, a conductive paint, a conductive label,and/or a conductive strap 172, for example, as illustrated in FIG. 8.The strap 172 may be made of a conductive material, such as metal. Thestrap 172 may be strapped onto the load control device 100 around theback side of the enclosure 126 extending from both sides 121 of the yoke120. The enclosure 126 may be a metalized enclosure made of a conductivematerial or infused with a conductive material. The conductive member170 may be a part of the enclosure 126 and/or inside of the enclosure.For example, the conductive member 170 may be integrated into theenclosure 126.

The yoke 120 may be approximately as wide as the enclosure 126, forexample, to provide for capacitive coupling between the conductivemember 170 and the yoke 120. If the load control device 100 is installedin a metal wallbox and the sides 121 of the yoke 120 (e.g., near thecenter of the yoke 120 where the conductive member 170 is capacitivelycoupled to the yoke) become electrically shorted to the metal wallbox,the communication range of the antenna at the communication frequencyf_(RF) may be affected. The load control device 100 may include anon-conductive element (not shown) to prevent the sides 121 of the yoke120 from contacting the metal wallbox. For example, the non-conductiveelement (e.g., electrical tape) may be adhered to the sides 121 of theyoke 120. The non-conductive cradle 132 may have tabs (not shown) thatextend out from the sides of the cradle 132 beyond the sides 121 of theyoke 120. The non-conductive cradle 132 may have flanges (not shown)that extend out from the sides of the cradle 132 and wrap around thesides 121 of the yoke 120. The non-conductive cradle 132 extend slightlybeyond the sides 121 of the yoke 120 (e.g., by approximately 0.040″).The non-conductive cradle 132 may have one or more nubs (not shown) thatare positioned in cut-outs (not shown) in the yoke 120, such that thenubs extend into the plane of the yoke 120 and extend beyond the sides121 of the yoke 120.

The load control device 100 may comprise one or more conductiveelements. For example, the load control device may comprise a conductivefaceplate (e.g., a conductive faceplate 180, a conductive faceplate 220,and/or the like) and/or a conductive backer (e.g., a conductive backer210, a conductive backer 230, and/or the like). The conductive elementsmay be partially or entirely made of a conductive material (e.g., ametallic material). The conductive elements may be capacitively coupledand/or electrically coupled to the driven element 150.

As described herein, a conductive faceplate may be installed on the loadcontrol device 100. FIG. 9 is a rear perspective view and FIG. 10A is afront view of an example conductive faceplate 180. FIG. 10B is a frontview of the driven element 150 of the antenna and FIG. 10C is a frontview of the conductive faceplate 180 and the driven element 150 overlaidon top of each other. FIG. 11 is a partial right side cross-sectionalview of the conductive faceplate 180. FIG. 12 is an enlarged perspectiveview of a conductive spring element 190 of the conductive faceplate 180.FIG. 13 is an enlarged partial top cross-section view of the loadcontrol device 100 with the conductive faceplate 180 installed.

The conductive faceplate 180 may include a conductive material 182,which for example, may be arranged over a plastic carrier 184. Theconductive material 182 may be, for example, a conductive sheet, aconductive paint, a conducive label, and/or the like. For example, theplastic carrier 184 may be approximately the same size and shape as theplastic faceplate 102. The conductive faceplate 180 may form an opening186 through which the bezel 114 of the load control device 100 mayextend when the conductive faceplate 180 is installed on the loadcontrol device 100. The conductive material 182 may be substantiallyplanar. For example, the conductive material 182 may be substantiallyplanar except for outer portions that may wrap around the edges of thefaceplate 180, for example, as illustrated in FIG. 9. For example, theconductive material 182 may be made from one or more metallic materials.The conductive material 182 may have one or more finishes. Examplefinishes for the conductive material 182 include satin nickel, antiquebrass, bright chrome, stainless steel, gold, clear anodized aluminum,etc. The plastic carrier 184 may include tabs 188 adapted to snap totabs 109 on the top and bottom edges of the adapter 104. Similar to theplastic faceplate 102, the opening 186 of the conductive faceplate 180may have a length L_(OPENING) of approximately 2.83 inches and a widthW_(OPENING) of approximately 0.17 inches. The conductive faceplate 180may have metallization on approximately 96% of the front surface. Theaspect ratio of the conductive faceplate 180 may range fromapproximately 3:1 to 20:1, and/or the conductive faceplate 180 may havemetallization on greater than or equal to approximately 85% of the frontsurface. The conductive faceplate 180 may be made entirely of metal. Forexample, the conductive faceplate 180 may not include the plasticcarrier 184. The conductive material 182 may be integrated into theconductive faceplate 180, for example, internal to the plastic carrier184.

The conductive material 182 may operate as a radiating element of theantenna. For example, the conductive material 182 may operate as theouter-most radiating element of the antenna when the conductivefaceplate 180 is installed on the load control device 100. In otherwords, the conductive faceplate 180 may have a conductive surface (e.g.,the conductive material 182). The conductive surface of the conductivefaceplate 180 may provide a radiating structure for the radio-frequencysignals transmitted from and/or received by the load control device 100(e.g., via the ambient air). When the conductive faceplate 180 isinstalled on the load control device 100, the conductive material 182may be located in a plane that is substantially parallel to a plane ofthe driven element 150 of the antenna. The conductive material 182 maybe offset from the driven element 150 by a distance DOFFSET-METAL (e.g.,approximately 0.113 inches) as shown in FIG. 13, such that theconductive material 182 is capacitively coupled to the driven element150. As a result, the geometry and/or dimensions of the opening 186 ofthe conductive faceplate 180 may be a part of the radiating element ofthe antenna. The conductive material 182 may be electrically coupleddirectly to the driven element 150 and/or the wireless communicationcircuit 160.

The conductive material 182 may be electrically coupled to the yoke 120at one point (e.g., to operate as a patch antenna). Accordingly, theload control device 100 may include a hybrid slot-patch antenna when theconductive faceplate 180 is installed on the load control device 100.The hybrid slot-patch antenna may be referred to as a slatch antenna.The conductive spring element 190 may operate to electrically couple theconductive material 182 to the yoke 120 through the screws 140 thatattach the bezel 114 to the yoke 120.

As exemplified in FIG. 12, the conductive spring element 190 may be bentat a joint 192. The conductive spring element 190 may include two legs194 that extend down to respective feet 196. The conductive springelement 190 may be received through an opening 198 in the plasticcarrier 184, such that the feet 196 are captured between the conductivematerial 182 and the plastic carrier 184, and the feet 196 contact aback side 199 of the conductive material 182. When the conductivefaceplate 180 is installed on the load control device 100, the joint 192contacts one of the screws 140 and the conductive spring element 190 iscompressed between the screw and the metallic plate 182. The conductivespring element 190 electrically couples together the metallic plate 182and the yoke 120 via one of the screws 140 that extends through one ofthe openings 154 in the driven element 150 as shown in FIG. 10C.

FIG. 14 is a simplified equivalent schematic diagram of the antenna ofthe load control device 100 when no faceplate and/or a plastic faceplate(e.g., a 100% plastic faceplate, such as the plastic faceplate 102) isinstalled on the load control device 100. FIG. 15 is a simplifiedequivalent schematic diagram of the antenna of the load control device100 when a conductive faceplate (e.g., the conductive faceplate 180) isinstalled on the load control device 100. The wireless communicationcircuit 160 may be located inside the enclosure 126. The conductivemember 170 may wrap around the enclosure 126 extending between the sidesof the yoke 120. As described herein, the conductive member 170 mayinclude conductive paint, label, and/or strap 172. The main slot 152 ofthe driven element 150 may be characterized by an inductance L_(SLOT1).The wireless communication circuit 160 is coupled to the driven element150 via two capacitors C₁, C₂, which are located on (e.g., mounted to)the front PCB 136. Each of the capacitors C₁, C₂ may have a capacitanceof, for example, approximately 2.2 pF. A capacitor C₃ (e.g., having acapacitance of approximately 4.3 pF) may be mounted to the front PCB136. The capacitor C₃ may be electrically coupled between the drivepoints (e.g., the legs 155) of the driven element 150.

Each side of the driven element 150 (e.g., sides separated by the mainslot 152) may be capacitively coupled through respective capacitancesC_(A1), C_(A2) to the touch sensitive device 130, which may becharacterized by a resistance R_(A). Each side of the driven element 150may be capacitively coupled to a common mode point. The common modepoint may include the electrical traces coupled to the LEDs 149 on thefront PCB 136. For example, a first side of the main slot 152 of thedriven element 150 may be coupled to the common mode point via theparallel combination of a capacitance C_(B1) and a resistance R_(B1). Asecond side of the main slot 152 of the driven element 150 may becoupled to the common mode point via the parallel combination of acapacitance C_(B2) and a resistance R_(B2). The yoke 120 may be coupledto the common mode point via a high impedance path that may include theseries combination of a capacitance C_(C1) and a resistance R_(C1).

When the conductive faceplate 180 is installed on the load controldevice 100 (e.g., as exemplified in FIG. 15), the sides of the drivenelement 150 may be capacitively coupled to the conductive material 182via respective capacitances C_(D1), C_(D2). Capacitances C_(D1), C_(D2)may have values that are dependent upon the distance DOFFSET-METALbetween the driven element 150 and the conductive material 182. Thesides of the main slot 152 of the driven element 150 may be capacitivelycoupled together via a capacitance C_(D3). Capacitance C_(D3) may have avalue that may depend upon the dimensions of the wrap-around slotportions 158 of the driven element 150. For example, the value ofcapacitance C_(D3) may depend on the amount of the main slot 152 of thedriven element 150 that does not overlap the opening 186 in theconductive material 182. The conductive material 182 may be directlyelectrically coupled to the driven element 150 and/or wirelesscommunication circuit 160, e.g., via two drive points located onopposite sides of the elongated opening at approximately the middle ofthe elongated opening.

The opening 186 in the conductive material 182 of the conductivefaceplate 180 may be characterized by an inductance L_(SLOT2). The sidesof the opening 186 in the conductive material 182 may be capacitivelycoupled to the common mode point through a first parallel combination ofa capacitance C_(E1) and a resistance R_(E1), and a second parallelcombination of a capacitance C_(E2) and a resistance R_(E2),respectively. The sides of the opening 186 of the conductive material182 may be coupled to the yoke 120 via respective high impedance pathsincluding a first series combination of a capacitance C_(F1) and aresistance R_(F1), and a second series combination of a capacitanceC_(F2) and a resistance R_(F2), respectively. The conductive material182 may be coupled to the yoke 120 through a low impedance path (e.g.,through the conductive spring element 190 and one of the screws 140), anexample of which is represented by the parallel combination of acapacitance C_(G1) and a resistance R_(G1) in FIG. 15.

FIG. 16 is a perspective view of an example multi-gang load controldevice installation 200 (e.g., a multi-gang control system). Forexample, a three-gang installation is shown in FIG. 16. The multi-ganginstallation 200 includes three load control devices installed in amulti-gang electrical wallbox (e.g., a three-gang wallbox). For example,each of the load control devices in the multi-gang installation 200 maybe the same as the load control device 100 described above. Themulti-gang installation 200 may include a multi-gang faceplate 202. Themulti-gang face plate 202 may have a front surface 204 and threeelongated openings 206A, 206B, 206C for receiving respective touchsensitive actuators 110A, 110B, 110C of the load control devices. Themulti-gang faceplate 202 may be a conductive multi-gage faceplate (e.g.,a metal multi-gang faceplate) and the front surface 204 may include aconductive material (e.g., similar to the single-gang conductivefaceplate 180). The conductive material may be made from one or moremetallic materials. The conductive material may be substantially planar.

The load control devices may each include an antenna having a respectivedriven element 150A, 150B, 150C. FIG. 17 is a front view of themulti-gang conductive faceplate 202 overlaid overtop of the drivenelements 150A, 150B, 150C. The multi-gang conductive faceplate 202 mayinclude three conductive spring elements 208A, 208B, 208C (e.g., eachsimilar to the conductive spring element 190 shown in FIGS. 11 and 12).The conductive spring elements 208A, 208B, 208C may each contact one ofthe screws 140 on the respective load control devices, such that theyoke 120 of each of the load control devices is electrically coupled tothe conductive material of the front surface 204 of the multi-gangconductive faceplate 202. The conductive spring elements 208A, 208B,208C may be configured to extend through respective openings 154A, 154B,154C of the driven elements 150A, 150B, 150C to contact the respectivescrews 140. As shown in FIG. 17, the conductive spring elements 208A,208B, 208C extend through the same opening 154A, 154B, 154C on each ofthe respective load control devices (e.g., the top left opening).

The conductive spring elements 208A, 208B, 208C may extend through thedifferent openings of the driven elements on each of the respective loadcontrol devices, for example, in order to optimize the efficiencies ofthe antennas of each of the load control devices in the multi-ganginstallation at the communication frequency f_(RF). FIG. 18 is a frontview of another example multi-gang conductive faceplate 202′ and thedriven elements 150A, 150B, 150C overlaid overtop of each other. Themulti-gang conductive faceplate 202′ may include conductive springelements 208B′ located near the bottom end of the middle opening 206B.The outer conductive spring elements 208A, 208C extend through the topleft opening 154A, 154C of the respective driven elements 150A, 105C.The conductive spring element 208B′ extends through an opening (e.g., alower left opening 154B′) of the middle driven element 150B that isrelatively different from the openings that conductive spring elements208A, 208C extend. Accordingly, the locations at which the drivenelements 150A, 150B, 150C are coupled to the conductive material of thefront surface 204 of the multi-gang conductive faceplate 202 may bedependent upon the communication frequency f_(RF) of the load controldevices.

As described herein, the impedance of the antenna of a load controldevice may be different based on whether the plastic faceplate 102, theconductive faceplate 180, or no faceplate is installed on the loadcontrol device. The communication frequency f_(RF) of the wirelesscommunication circuit 160 may be selected and/or the structure of theload control device may be designed, such that the communication rangeof the load control device at the communication frequency f_(RF) isacceptable independent of whether the plastic faceplate 102, or theconductive faceplate 180 is installed. The communication range may beacceptable, for example, when the load control device is able tosuccessfully receive and/or transmit RF signals. The load control device100 may be characterized by a first communication range R₁ at thecommunication frequency f_(RF) when the plastic faceplate 102, or nofaceplate is installed. The load control device may be characterized bya second communication range R₂ when the conductive faceplate 180 isinstalled. The second communication range R₂ may be greater than thefirst communication range R₁. The first communication range R₁ may begreater than or equal to a minimum acceptable communication rangeR_(MIN) (e.g., approximately 30 feet), such that the load control deviceis able to properly transmit and receive the RF signals when the plasticfaceplate 102, or no faceplate is installed.

A faceplate (e.g., the plastic faceplate 102) may include a conductivebacker 210. The conductive backer 210 may operate to bring the impedanceof the antenna when the plastic faceplate 102 is installed closer to theimpedance of the antenna when the conductive faceplate 180 is installed.The conductive backer 210 may comprise a conductive material, such as,for example, a metallic sheet and/or the like. The conductive backer 210may be made from one or more metallic materials.

FIG. 19 is a rear perspective view of a plastic faceplate 102 having theconductive backer 210 attached to a rear surface 212 of the faceplate102. FIG. 20 is a partial exploded view of the load control device 100illustrating the plastic faceplate 102, where the adapter plate 104 hasbeen removed from the load control device 100 and the conductive backer210 has been removed from the plastic faceplate 102. FIG. 21 is a rightside cross-sectional view of the load control device 100 taken throughthe center of the load control device 100 (e.g., as shown in FIG. 2)with the conductive backer 210 attached to the plastic faceplate 102.FIG. 22 is a top side cross-sectional view and FIG. 23 is an enlargedpartial top side cross-sectional view of the load control device 100taken through the center of the load control device (e.g., as shown inFIG. 2) with the conductive backer 210 attached to the plastic faceplate102. FIG. 24A is a front view of the conductive backer 210, and FIG. 24Bis a front view of the driven element 150 of the antenna of the loadcontrol device 100. FIG. 24C is a front view of the plastic faceplate102, the conductive backer 210, and the driven element 150 overlaidovertop of each other.

When the plastic faceplate 102 having the conductive backer 210 isinstalled on the load control device 100, the conductive backer 210 maymimic the structure of the conductive material 182. The conductivebacker 210 may operate as the radiating element of the antenna. Forexample, the conductive backer 210 may operate as the outer-mostradiating element of the antenna if the plastic faceplate 102 having theconductive backer 210 is installed on the load control device 100. Theconductive backer 210 may act as a radiating element and as a capacitivecoupling member when the conductive faceplate 180 is installed on theload control device 100, and in such instances, the conductive faceplate180 (e.g., the conductive material 182) may act as the outer-mostradiating element of the antenna. For example, the conductive backer 210may capacitively couple the conductive faceplate 180 to the drivenelement 150.

The conductive backer 210 may be located in a plane that issubstantially parallel to a plane of the driven element 150 of theantenna, for example, as with the conductive material 182. Theconductive backer 210 may be offset from the driven element 150 by adistance DOFFSET-PLASTIC (e.g., approximately 0.050 inches), for exampleas shown in FIG. 23. The conductive backer 210 may be directly connectedor capacitively coupled to the opposite sides 121 of the yoke 120. Theconductive elements 210 may be capacitively coupled to the drivenelement 150. The conductive backer 210 may include a central slot 214that extends along the longitudinal axis of the load control device 100.The central slot 214 may be approximately the same size as the opening106 in the plastic faceplate 102.

The conductive backer 210 may be electrically coupled to the yoke 120 atone point, such that the antenna may operate as a patch antenna (e.g., ahybrid slot-patch, or slatch antenna). The conductive backer 210 mayinclude a contact member 216. The contact member 216 may be formed aspart of the conductive backer 210. The contact member 216 may beelongated. The contact member 216 may be biased towards the load controldevice 100. When the plastic faceplate 102 with the conductive backer210 is installed on the load control device 100, the contact member 216may contact one of the screws 140 that attaches the bezel 114 to theyoke 120 to electrically couple the conductive backer 210 to the yoke120. The contact member 216 may be wider at the base where the contactmember 216 meets the conductive backer 210 (e.g., as shown in FIGS.26-27C). The contact member 216 may be of any shape, size, or structureto provide electrical connection between the conductive backer 210 andone of the screws 140. The conductive backer 210 may include wrap-aroundslot portions 218. The dimensions of the wrap-around slot portions 218may be adjusted to change the impedance of the antenna, as describedherein.

The conductive backer 210 may be formed as a part of the plasticfaceplate 102, e.g., integrated onto a back surface of the plasticfaceplate 102 or internal to the plastic faceplate 102. The conductivebacker 210 may be attached to the adapter plate 104 (e.g., the front orrear surface of the adapter plate). The conductive element 210 may beelectrically coupled to the yoke 120 via one of two conductive faceplatescrews received through the openings 124 in the adapter and the openings125 in the yoke 120.

FIG. 25 is a simplified equivalent schematic diagram of the antenna ofthe load control device 100 when the plastic faceplate 102 with theconductive backer 210 is installed on the load control device. Thecentral slot 214 of the conductive backer 210 may be characterized by aninductance L_(SLOT3). The conductive backer 210 may be coupled to theyoke 120 through a low impedance path (e.g., through the contact member216 and one of the screws 140), an example of which is represented bythe series combination of an inductance L_(H1) and a resistance R_(H1)in FIG. 25. A distance DOFFSET-PLASTIC may refer to a distance betweenthe driven element 150 and the conductive backer 210 on the plasticfaceplate 102. A distance DOFFSET-METAL may refer to a distance betweenthe driven element 150 and the metallic plate 182 of the conductivefaceplate 180. The distance DOFFSET-PLASTIC may be smaller than thedistance DOFFSET-METAL. The values of the capacitances C_(D1), C_(D2) ofthe capacitive coupling between the conductive backer 210 and the drivenelement 150 may be larger, for example, because the distanceDOFFSET-PLASTIC may be smaller than the distance DOFFSET-METAL.

The value of the capacitance C_(D3) between the sides of the main slot152 of the driven element 150 may depend on the size of the wrap-aroundslot portions 218 of the conductive backer 210, for example, as comparedto the size of the wrap-around slot portions 158 of the driven element150. As the amount of overlap of the wrap-around slot portions 218 ofthe conductive backer 210 and the wrap-around slot portions 158 of thedrive element increases, the value of the capacitance C_(D3) between thesides of the main slot 152 of the driven element 150 may decrease, andvice versa. The dimensions (e.g., the lengths) of the wrap-around slotportions 218 of the conductive backer 210 may be adjusted to change thevalue of the capacitance C_(D3). The value of the capacitance C_(D3) maybe changed to bring the impedance of the antenna with the plasticfaceplate 102 having the conductive backer 210 being installed closer tothe impedance of the antenna when the conductive faceplate 180 isinstalled. For example, the lengths of the wrap-around slot portions 218of the conductive backer 210 may be increased and/or the widths of thewrap-around slot portions 218 may be increased to change the value ofthe capacitance C_(D3). Increasing the lengths of the wrap-around slotportions 218 and/or the widths of the wrap-around slot portions 218 maybring the impedance of the antenna when the plastic faceplate 102 havingthe conductive backer 210 is installed closer to the impedance of theantenna when the conductive faceplate 180 is installed. Accordingly, theconductive backer 210 may provide a capacitive loading on the antennathat is approximately equal to the capacitive loading provided by theconductive faceplate 180 that has an equivalent size and shape as theplastic faceplate 102.

A conductive backer 210 may be mounted to a rear surface of the plasticcarrier 184 of the conductive faceplate 180 (e.g., as shown in FIG. 9).FIG. 26 is a rear perspective view, and FIG. 27A is a front view of anexample conductive faceplate 220 having a conductive backer 230. FIG.27B is a front view of the driven element 150 of the antenna, and FIG.27C is a front view of the conductive faceplate 220, the conductivebacker 230, and the driven element 150 overlaid overtop of each other.The conductive faceplate 220 may include a conductive material 222arranged over a plastic carrier 224. The conductive material 222 may be,for example, a conductive sheet, a conductive paint, a conductive label,and/or the like.

The conductive faceplate 220 may form an opening 226 through which thebezel 114 of the load control device 100 may extend when the conductivefaceplate 220 is installed on the load control device 100. For example,the plastic carrier 224 and the opening 226 of the conductive faceplate222 may be approximately the same size and shape as the plastic carrier184 and the opening 186, respectively, of the conductive faceplate 180shown in FIG. 9. The conductive material 222 may be substantiallyplanar. For example, the conductive material 222 may be substantiallyplanar except for the portions that wrap around the edges of thefaceplate 220, for example, as shown in FIG. 26. The conductive material222 may be made from one or more conductive, metallic materials. Theconductive material 222 may one or more finishes. Example finishesinclude satin nickel, antique brass, bright chrome, stainless steel,gold, clear anodized aluminum, etc. The plastic carrier 224 may includetabs 228. The tabs 228 may be adapted to snap to tabs 109 on the top andbottom edges of the adapter 104. The conductive faceplate 220 may havemetallization on approximately 96% of the front surface. The aspectratio of the conductive faceplate 220 may range from approximately 3:1to 20:1, and/or the conductive faceplate 220 may have metallization ongreater than or equal to approximately 85% of the front surface. Theconductive faceplate 220 may be made entirely of metal. For example, theconductive faceplate 220 may not include the plastic carrier 224. Theconductive material 222 may be integrated into the conductive faceplate220, for example, internal to the plastic carrier 224.

The conductive backer 230 may include a conductive material, such as,for example, a metallic sheet, a conductive label, a conductive paint,and/or the like. The conductive backer 230 may be attached to a rearsurface 232 of the plastic carrier 224 of the conductive faceplate 220.When the conductive faceplate 220 is installed on the load controldevice 100, the conductive backer 230 may be offset from the drivenelement 150 by a distance DOFFSET-BACKER (e.g., similar to the distanceDOFFSET-PLASTIC, such as approximately 0.050 inches). The conductivebacker 230 may include a central slot 234 that extends along thelongitudinal axis of the load control device 100. The central slot 234may be approximately the same size as the opening 226 in the plasticcarrier 224. The conductive material 222 and the conductive backer 230may be located in respective planes that are substantially parallel tothe plane of the driven element 150 of the antenna. The conductivematerial 222 of the conductive faceplate 220 may act as the outer-mostradiating element of the antenna, for example, when the conductivefaceplate 220 is installed on the load control device 100. Theconductive backer 230 may act as the outer-most radiating element of theantenna, for example, when the conductive faceplate 220 is not installedon the load control device 100. If the conductive faceplate 220 isinstalled on the load control device 100, then the conductive backer 230may act as a radiating element and the conductive material 222 may actas the outer-most radiating element of the antenna.

The conductive backer 230 may be electrically coupled to the yoke 120 atone point, such that the antenna also operates as a patch antenna (e.g.,a hybrid slot-patch, or slatch antenna). The conductive backer 230 mayinclude a contact member 236. The contact member 236 may be formed aspart of the conductive backer 230. The contact member 236 may be biasedtowards the load control device 100. The contact member 236 may betriangularly-shaped and may be wider at the base than the contact member216 of the conductive backer 210, for example, as shown in FIG. 19. Whenthe conductive faceplate 220 is installed on the load control device100, the contact member 236 may contact one of the screws 140 thatattaches the bezel 114 to the yoke 120 to thus electrically couple theconductive backer 230 to the yoke 120. The contact member 216 may benarrower than the contact member 236, for example, as shown in FIGS. 19and 26. The contact member 236 may be of any shape, size, or structureto provide electrical connection between the conductive backer 230 andone of the screws 140. The conductive backer 230 may provide consistencyin the RF communication range of the load control device at thecommunication frequency f_(RF) independent of the type of metallicmaterial, or finish of the conductive material 222. The conductivebacker 230 may provide for consistency with the electrical connectionbetween the conductive backer 230 and the yoke 120 independent of thetype of metallic material or finish of the conductive material 222.

The conductive backer 230 may include wrap-around slot portions 238. Thewrap-around slot portions 238 may have dimensions that may be adjustedto change the impedance of the antenna. The slot portions 238 of theconductive backer 230 mounted to the conductive faceplate 220 may besized and shaped to bring the impedance of the antenna when theconductive faceplate 220 with the conductive backer 230 is installedcloser to the impedance of the antenna when the plastic faceplate 102with the conductive backer 210 is installed. For example, the slotportions 238 of the conductive backer 230 mounted to the conductivefaceplate 220 may be longer than the slot portions 218 of the conductivebacker 210 mounted to the plastic faceplate 102 that are shown in FIG.19. The slot portions 238 of the conductive backer 230 mounted to theconductive faceplate 220 may be sized and shaped, for example, to matchthe size and shape of the main slot 152 of the driven element 150 (e.g.,as shown in FIG. 27C). A width W_(CE) of the conductive backer 230 ofthe conductive faceplate 220 may be adjusted (e.g., trimmed) to bringthe impedance of the antenna when the conductive faceplate 220 with theconductive backer 230 is installed closer to the impedance of theantenna when the plastic faceplate 102 with the conductive backer 210 isinstalled.

FIG. 28 is a simplified equivalent schematic diagram of the antenna ofthe load control device 100 when the conductive faceplate 220 isinstalled on the load control device 100. The conductive backer 230 ofthe conductive faceplate 220 may be coupled to the yoke 120 through alow impedance path (e.g., through the contact member 236 and one of thescrews 140), an example of which is represented by the seriescombination of an inductance L_(J1) and a resistance R_(J1) in FIG. 28.The opening 226 in the conductive material 222 of the conductivefaceplate 220 may be characterized by the inductance L_(SLOT2). Theconductive backer 230 may be capacitively coupled to conductive material222 on each side of the opening 226 via respective capacitances C_(K1),C_(K2). The combination of the conductive material 222 and theconductive backer 230 of the conductive faceplate 220 may provide acapacitive loading on the antenna that is approximately equal to thecapacitive loading provided by the plastic faceplate 102 with theconductive backer 210.

FIG. 29 is a perspective view of an example wireless control device 250,e.g., a keypad device. The wireless control device 250 may include afaceplate 252 having an opening 254 for receiving a plurality of buttons256. The faceplate 252 may be adapted to connect to an adapter plate 258(e.g., in a similar manner as the faceplate 102 connects to the adapterplate 104). The wireless control device 250 may be configured totransmit RF signals in response to actuations of the buttons 256. Thefaceplate 252 may include a conductive faceplate. The faceplate 252 mayinclude a conductive material arranged over a plastic carrier (e.g.,such as the conductive faceplate 180). The buttons 256 may be made of anon-conductive material, such as plastic or glass. The wireless controldevice 250 may include an antenna having a driven element that iscapacitively coupled to the conductive material of the faceplate 252,such that the conductive material operates as a radiating element of theantenna. The conductive material of the faceplate 252 may be directlyelectrically coupled to a yoke of the wireless control device 250 at asingle electrical connection. The buttons 256 may be made of aconductive material, for example, a metallic sheet attached to a plasticcarrier.

FIG. 30 is a simplified block diagram of an example load control device300 that may be deployed as, for example, the load control device 100shown in FIG. 1-28. The load control device 300 may include a hotterminal H that may be adapted to be coupled to an AC power source 302.The load control device 300 may include a dimmed hot terminal DH thatmay be adapted to be coupled to an electrical load, such as a lightingload 304. The load control device 300 may include a controllablyconductive device 310 coupled in series electrical connection betweenthe AC power source 302 and the lighting load 304. The controllablyconductive device 310 may control the power delivered to the lightingload. The controllably conductive device 310 may include a suitable typeof bidirectional semiconductor switch, such as, for example, a triac, afield-effect transistor (FET) in a rectifier bridge, two FETs inanti-series connection, or one or more insulated-gate bipolar junctiontransistors (IGBTs). An air-gap switch 329 may be coupled in series withthe controllably conductive device 310. The air-gap switch 329 may beopened and closed in response to actuations of an air-gap actuator(e.g., the air-gap switch actuator 129). When the air-gap switch 329 isclosed, the controllably conductive device 310 is operable to conductcurrent to the load. When the air-gap switch 329 is open, the lightingload 304 is disconnected from the AC power source 302.

The load control device 300 may include a control circuit 314. Thecontrol circuit 314 may include one or more of a processor (e.g., amicroprocessor), a microcontroller, a programmable logic device (PLD), afield programmable gate array (FPGA), an application specific integratedcircuit (ASIC), or any suitable controller or processing device. Thecontrol circuit 314 may be operatively coupled to a control input of thecontrollably conductive device 310, for example, via a gate drivecircuit 312. The control circuit 314 may be used for rendering thecontrollably conductive device 310 conductive or non-conductive, forexample, to control the amount of power delivered to the lighting load304. The control circuit 314 may receive inputs from a touch sensitiveactuator 316 (e.g., the touch sensitive actuator 110). The controlcircuit 314 may individually control LEDs 318 (e.g., the LEDs 149) toilluminate a linear array of visual indicators on the touch sensitiveactuator.

The control circuit 314 may receive a control signal representative ofthe zero-crossing points of the AC main line voltage of the AC powersource 302 from a zero-crossing detector 319. The control circuit 314may be operable to render the controllably conductive device 310conductive and/or non-conductive at predetermined times relative to thezero-crossing points of the AC waveform using a phase-control dimmingtechnique. Examples of dimmers are described in greater detail incommonly-assigned U.S. Pat. No. 7,242,150, issued Jul. 10, 2007,entitled DIMMER HAVING A POWER SUPPLY MONITORING CIRCUIT; U.S. Pat. No.7,546,473, issued Jun. 9, 2009, entitled DIMMER HAVING AMICROPROCESSOR-CONTROLLED POWER SUPPLY; and U.S. Pat. No. 8,664,881,issued Mar. 4, 2014, entitled TWO-WIRE DIMMER SWITCH FOR LOW-POWERLOADS, the entire disclosures of which are hereby incorporated byreference.

The load control device 300 may include a memory 320. The memory 320 maybe communicatively coupled to the control circuit 314 for the storageand/or retrieval of, for example, operational settings, such as,lighting presets and associated preset light intensities. The memory 320may be implemented as an external integrated circuit (IC) or as aninternal circuit of the control circuit 314. The load control device 300may include a power supply 322. The power supply 322 may generate adirect-current (DC) supply voltage V_(CC) for powering the controlcircuit 314 and the other low-voltage circuitry of the load controldevice 300. The power supply 322 may be coupled in parallel with thecontrollably conductive device 310. The power supply 322 may be operableto conduct a charging current through the lighting load 304 to generatethe DC supply voltage V_(CC).

The load control device 300 may include a wireless communication circuit324 (e.g., the wireless communication circuit 160). The wirelesscommunication circuit 324 may include a RF transceiver coupled to anantenna for transmitting and/or receiving RF signals. For example, theantenna may include the slot or slatch antenna of the load controldevice 100 shown in FIG. 1-28. The control circuit 314 may be coupled tothe wireless communication circuit 324 for transmitting and/or receivingdigital messages via the RF signals. The control circuit 314 may beoperable to control the controllably conductive device 310 to adjust theintensity of the lighting load 304 in response to the digital messagesreceived via the RF signals. The control circuit 314 may transmitfeedback information regarding the amount of power being delivered tothe lighting load 304 via the digital messages included in the RFsignals. The control circuit 314 may be configured to transmit RFsignals while the touch sensitive actuator 316 is being actuated, sincethe communication range of the antenna may be temporarily increasedwhile a user's finger is adjacent the main slot 152 of the drivenelement 150. The wireless communication circuit 324 may include an RFtransmitter for transmitting RF signals, an RF receiver for receiving RFsignals, or an infrared (IR) transmitter and/or receiver fortransmitting and/or receiving IR signals.

FIG. 31 is a simple diagram of an example load control system 400 (e.g.,a lighting control system) in which a wall-mounted load control device410 having a thin touch sensitive actuator (e.g., the load controldevice 100 and/or the load control device 300) may be deployed. Thewall-mounted load control device 410 may be coupled in series electricalconnection between an AC power source 402 and a first lighting load,e.g., a first light bulb 412 installed in a ceiling mounted downlightfixture 414. The first light bulb 412 may be installed in a wall-mountedlighting fixture or other lighting fixture mounted to another surface.The wall-mounted load control device 410 may be adapted to bewall-mounted in a standard electrical wallbox. The load control system400 may include another load control device, e.g., a plug-in loadcontrol device 420. The plug-in load control device 420 may be coupledin series electrical connection between the AC power source 402 and asecond lighting load, e.g., a second light bulb 422 installed in a lamp(e.g., a table lamp 424). The plug-in load control device 420 may beplugged into an electrical receptacle 426 that is powered by the ACpower source 402. The table lamp 424 may be plugged into the plug-inload control device 420. The second light bulb 422 may be installed in atable lamp or other lamp that may be plugged into the plug-in loadcontrol device 420. The plug-in load control device 420 may beimplemented as a table-top load control device, or a remotely-mountedload control device.

The wall-mounted load control device 410 may include a touch sensitiveactuator 416 (e.g., the touch sensitive actuator 110 of the load controldevice 100 or the touch sensitive actuator 316 of the load controldevice 300) for controlling the light bulb 412. In response to actuationof the touch sensitive actuator 416, the wall-mounted load controldevice 410 may be configured to turn the light bulb 412 on and off, andto increase or decrease the amount of power delivered to the light bulb.The wall-mounted load control device 410 may vary the intensity of thelight bulb by varying the amount of power delivered to the light bulb.The wall-mounted load control device 410 may increase or decrease theintensity of the light bulb from a minimum intensity (e.g.,approximately 1%) to a maximum intensity (e.g., approximately 100%). Thewall-mounted load control device 410 may be configured to provide visualindicators. The visual indicators may be arranged in a linear array onthe touch sensitive actuator 416. The wall-mounted load control device410 may be configured to illuminate the visual indicators to providefeedback of the intensity of the light bulb 412. Examples ofwall-mounted dimmer switches are described in greater detail in U.S.Pat. No. 5,248,919, issued Sep. 29, 1993, entitled LIGHTING CONTROLDEVICE, and U.S. patent application Ser. No. 13/780,514, filed Feb. 28,2013, entitled WIRELESS LOAD CONTROL DEVICE, the entire disclosures ofwhich are hereby incorporated by reference.

The load control system 400 may include a daylight control device, e.g.,a motorized window treatment 430, mounted in front of a window forcontrolling the amount of daylight entering the space in which the loadcontrol system 400 is installed. The motorized window treatment 430 mayinclude, for example, a cellular shade, a roller shade, a drapery, aRoman shade, a Venetian blind, a Persian blind, a pleated blind, atensioned roller shade systems, or other suitable motorized windowcovering. The motorized window treatment 430 may include a motor driveunit 432 for adjusting the position of a covering material 434 of themotorized window treatment (e.g., a cellular shade fabric as shown inFIG. 1) in order to control the amount of daylight entering the space.The motor drive unit 432 of the motorized window treatment 430 may havean RF receiver and an antenna mounted on or extending from a motor driveunit of the motorized window treatment. The motor drive unit 432 of themotorized window treatment 430 may be battery-powered or may receivepower from an external direct-current (DC) power supply. Examples ofbattery-powered motorized window treatments are described in greaterdetail in commonly-assigned U.S. Patent Application Publication No.2012/0261078, published Oct. 18, 2012, entitled MOTORIZED WINDOWTREATMENT, and U.S. patent application Ser. No. 13/798,946, filed Mar.13, 2013, entitled BATTERY-POWERED ROLLER SHADE SYSTEM, the entiredisclosures of which are hereby incorporated by reference.

The load control system 400 may include one or more input devices, e.g.,RF transmitters, such as a wall-mounted remote control device 440, abattery-powered handheld remote control device 450, an occupancy sensor460, or a daylight sensor 470. The wall-mounted load control device 410and/or the plug-in load control device 420 may be configured to receivedigital messages via wireless signals, e.g., radio-frequency (RF)signals 406. The wireless signals may be transmitted by the wall-mountedremote control device 440, the battery-powered remote control device450, the occupancy sensor 460, or the daylight sensor 470. In responseto the received digital messages, the wall-mounted load control device410 and/or the plug-in load control device 420 may be configured to turnthe respective light bulb 412, 422 on and off, and to increase ordecrease the intensity of the respective light bulb. The wall-mountedload control device 410 and/or the plug-in load control device 420 maybe implemented as electronic switches configured to turn on and off(e.g., only turn on and off) the respective light bulbs 412, 422.

The wall-mounted remote control device 440 may include a thin touchsensitive actuator 442 (e.g., similar to the touch sensitive actuator416 of the wall-mounted load control device 410). The wall-mountedremote control device 440 may not include an internal load controlcircuit. The wall-mounted remote control device 440 may not directly beconnected to an electrical load. The wall-mounted remote control device440 may transmit RF signals 406 in response to actuations of the touchsensitive actuator 442. For example, the RF signals 406 may betransmitted at a communication frequency f_(RF) (e.g., approximately 434MHz) using a proprietary RF protocol, such as the ClearConnect®protocol. The wall-mounted load control device 410 may be configured toreceive the RF signals transmitted by the wall-mounted remote controldevice 440, for example, to control the light bulb 412 in response toactuations of the thin touch sensitive actuator 442 of the wall-mountedremote control device 440. The RF signals 406 may be transmitted at adifferent communication frequency, such as, for example, 2.4 GHz or 5.6GHz. The RF signals 406 may be transmitted using a different RFprotocol, such as, for example, one of WIFI, ZIGBEE, Z-WAVE, KNX-RF,ENOCEAN RADIO protocols, or a different proprietary protocol.

The battery-powered remote control device 450 may include one or moreactuators 452 (e.g., one or more of an on button, an off button, a raisebutton, a lower button, and a preset button). The battery-powered remotecontrol device 450 may transmit RF signals 406 in response to actuationsof one or more of the actuators 452. The battery-powered remote controldevice 450 may be handheld. The battery-powered remote control device450 may be mounted vertically to a wall, or supported on a pedestal tobe mounted on a tabletop. Examples of battery-powered remote controldevices are described in greater detail in commonly-assigned U.S. Pat.No. 8,330,638, issued Dec. 11, 2012, entitled WIRELESS BATTERY-POWEREDREMOTE CONTROL HAVING MULTIPLE MOUNTING MEANS, and U.S. PatentApplication Publication No. 2012/0286940, published Nov. 12, 2012,entitled CONTROL DEVICE HAVING A NIGHTLIGHT, the entire disclosures ofwhich are hereby incorporated by reference.

The occupancy sensor 460 may be configured to detect occupancy andvacancy conditions in the space in which the load control system 400 isinstalled. The occupancy sensor 460 may transmit digital messages to thewall-mounted load control device 410 and/or the plug-in load controldevice 420 via the RF signals 406 in response to detecting the occupancyor vacancy conditions. The wall-mounted load control device 410 and/orthe plug-in load control device 420 may be configured to turn on therespective light bulb 412, 422 in response to receiving an occupiedcommand. The wall-mounted load control device 410 and/or the plug-inload control device 420 may be configured to turn off the respectivelight bulb in response to receiving a vacant command. The occupancysensor 460 may operate as a vacancy sensor to turn off (e.g., only turnoff) the lighting loads in response to detecting a vacancy condition(e.g., to not turn on the light bulbs 412, 422 in response to detectingan occupancy condition). Examples of RF load control systems havingoccupancy and vacancy sensors are described in greater detail incommonly-assigned U.S. Pat. No. 8,009,042, issued Aug. 30, 2011 Sep. 3,2008, entitled RADIO-FREQUENCY LIGHTING CONTROL SYSTEM WITH OCCUPANCYSENSING; U.S. Pat. No. 8,199,010, issued Jun. 12, 2012, entitled METHODAND APPARATUS FOR CONFIGURING A WIRELESS SENSOR; and U.S. Pat. No.8,228,184, issued Jul. 24, 2012, entitled BATTERY-POWERED OCCUPANCYSENSOR, the entire disclosures of which are hereby incorporated byreference.

The daylight sensor 470 may be configured to measure a total lightintensity in the space in which the load control system is installed.The daylight sensor 470 may transmit digital messages including themeasured light intensity to the wall-mounted load control device 410and/or the plug-in load control device 420. The daylight sensor 470 maytransmit digital messages via the RF signals 406 for controlling theintensities of the respective light bulbs 412, 422 in response to themeasured light intensity. Examples of RF load control systems havingdaylight sensors are described in greater detail in commonly-assignedU.S. Pat. No. 8,410,706, issued Apr. 2, 2013, entitled METHOD OFCALIBRATING A DAYLIGHT SENSOR; and U.S. Pat. No. 8,451,116, issued May28, 2013, entitled WIRELESS BATTERY-POWERED DAYLIGHT SENSOR, the entiredisclosures of which are hereby incorporated by reference.

Digital messages transmitted by the input devices (e.g., thewall-mounted remote control device 440, the battery-powered remotecontrol device 450, the occupancy sensor 460, and the daylight sensor470) may include a command and identifying information, for example, aserial number (e.g., a unique identifier) associated with thetransmitting input device. Each of the input devices may be assigned tothe wall-mounted load control device 410 and/or the plug-in load controldevice 420 during a configuration procedure of the load control system400, such that the wall-mounted load control device 410 and/or theplug-in load control device 420 are responsive to digital messagestransmitted by the input devices via the RF signals 406. Examples ofmethods of associating wireless control devices are described in greaterdetail in commonly-assigned U.S. Patent Application Publication No.2008/0111491, published May 15, 2008, entitled RADIO-FREQUENCY LIGHTINGCONTROL SYSTEM, and U.S. Patent Application Publication No.2013/0214609, published Aug. 22, 2013, entitled TWO-PART LOAD CONTROLSYSTEM MOUNTABLE TO A SINGLE ELECTRICAL WALLBOX, the entire disclosuresof which are hereby incorporated by reference.

The load control system 400 may include a gateway device 480 (e.g., abridge) configured to enable communication with a network 482, e.g., awireless or wired local area network (LAN). The gateway device 480 maybe connected to a router (not shown) via a wired digital communicationlink 484 (e.g., an Ethernet communication link). The router may allowfor communication with the network 482, e.g., for access to theInternet. The gateway device 480 may be wirelessly connected to thenetwork 482, e.g., using Wi-Fi technology.

The gateway device 480 may be configured to transmit RF signals 406 tothe wall-mounted load control device 410 and/or the plug-in load controldevice 420 (e.g., using the proprietary protocol) for controlling therespective light bulbs 412, 422 in response to digital messages receivedfrom external devices via the network 482. The gateway device 480 may beconfigured to receive RF signals 406 from the wall-mounted load controldevice 410, the plug-in load control device 420, the motorized windowtreatment 430, the wall-mounted remote control device 440, thebattery-powered remote control device 450, the occupancy sensor 460,and/or the daylight sensor 470 (e.g., using the proprietary protocol).The gateway device 480 may be configured to transmit digital messagesvia the network 482 for providing data (e.g., status information) toexternal devices. The gateway device 480 may operate as a centralcontroller for the load control system 400, or may simply relay digitalmessages between the control devices of the load control system and thenetwork 482.

The load control system 400 may include a network device 490, such as, asmart phone (for example, an iPhone® smart phone, an Android® smartphone, or a Blackberry® smart phone), a personal computer, a laptop, awireless-capable media device (e.g., MP3 player, gaming device, ortelevision), a tablet device, (for example, an iPad® hand-held computingdevice), a Wi-Fi or wireless-communication-capable television, or anyother suitable Internet-Protocol-enabled device. The network device 490may be operable to transmit digital messages in one or more InternetProtocol packets to the gateway device 480 via RF signals 408 eitherdirectly or via the network 482. For example, the network device 490 maytransmit the RF signals 408 to the gateway device 480 via a Wi-Ficommunication link, a Wi-MAX communications link, a Bluetooth®communications link, a near field communication (NFC) link, a cellularcommunications link, a television white space (TVWS) communication link,or any combination thereof. Examples of load control systems operable tocommunicate with network devices on a network are described in greaterdetail in commonly-assigned U.S. Patent Application Publication No.2013/0030589, published Jan. 31, 2013, entitled LOAD CONTROL DEVICEHAVING INTERNET CONNECTIVITY, the entire disclosure of which is herebyincorporated by reference.

The network device 490 may include a visual display 492. The visualdisplay 492 may include a touch screen that may include, for example, acapacitive touch pad displaced overtop the visual display, such that thevisual display may display soft buttons that may be actuated by a user.The network device 490 may include a plurality of hard buttons, e.g.,physical buttons (not shown), in addition to the visual display 492. Thenetwork device 490 may download a product control application forallowing a user of the network device to control the load control system400. In response to actuations of the displayed soft buttons or hardbuttons, the network device 490 may transmit digital messages to thegateway device 480 through the wireless communications described herein.The network device 490 may transmit digital messages to the gatewaydevice 480 via the RF signals 408 for controlling the wall-mounted loadcontrol device 410 and/or the plug-in load control device 420. Thegateway device 480 may be configured to transmit RF signals 408 to thenetwork device 490 in response to digital messages received from thewall-mounted load control device 410, the plug-in load control device420, the motorized window treatment 430, the wall-mounted remote controldevice 440, the battery-powered remote control device 450, the occupancysensor 460, and/or the daylight sensor 470 (e.g., using the proprietaryprotocol) for displaying data (e.g., status information) on the visualdisplay 492 of the network device.

The operation of the load control system 400 may be programmed andconfigured using the gateway device 480 and/or network device 490. Anexample of a configuration procedure for a wireless load control systemis described in greater detail in commonly-assigned U.S. patentapplication Ser. No. 13/830,237, filed Mar. 14, 2013, entitledCOMMISSIONING LOAD CONTROL SYSTEMS, the entire disclosure of which ishereby incorporated by reference.

When the load control system 400 is being installed and/or configured,the wall-mounted load control device 410 may be installed without afaceplate. When no faceplate is installed, the wall-mounted load controldevice 410 may be characterized by a first communication range R₁ at thecommunication frequency f_(RF). When an appropriate faceplate (e.g., theconductive faceplate 180, 220 or the plastic faceplate 102 having theconductive backer 210, 230) is installed, the wall-mounted load controldevice 410 may be characterized by a second communication range R₂greater than the first communication range R₁. The first communicationrange R₁ may be greater than or equal to a minimum acceptablecommunication range R_(MIN) (e.g., approximately 30 feet), such that theload control device is able to properly transmit and receive the RFsignals if no faceplate is installed while the load control system 400is being installed and/or configured.

The wall-mounted load control device 400 may include a temporaryradiating element (not shown) affixed to a front surface of the bezel(e.g., the bezel 114) for re-tuning the antenna of the control devicewhile the load control system 400 is being installed and/or configured.The temporary radiating element may operate in a similar manner as theconductive backer 210 on the plastic faceplate 102. The temporaryradiating element may increase the communication range of thewall-mounted load control device 400 at the communication frequencyf_(RF) while the load control system 400 is being installed and/orconfigured. For example, the temporary radiating element may comprise alabel affixed to the front surface of the bezel 114, where the label hasan internal conductive element. After the load control system 400 isinstalled and configured, the temporary radiating element may be removedfrom the bezel 114 and the appropriate faceplate (e.g., the conductivefaceplate 180, the plastic faceplate 102 having the conductive backer210, or the conductive faceplate 220 having the conductive backer 230)may be installed on the wall-mounted load control device 400.

Examples of wireless load control systems are described in greaterdetail in commonly-assigned U.S. Pat. No. 5,905,442, issued May 18,1999, entitled METHOD AND APPARATUS FOR CONTROLLING AND DETERMINING THESTATUS OF ELECTRICAL DEVICES FROM REMOTE LOCATIONS; and U.S. patentapplication Ser. No. 12/033,223, filed Feb. 19, 2008, entitledCOMMUNICATION PROTOCOL FOR A RADIO-FREQUENCY LOAD CONTROL SYSTEM, theentire disclosures of all of which are hereby incorporated by reference.

What is claimed is:
 1. A wall-mountable wireless control devicecomprising: an antenna configured to transmit or receive radio-frequencysignals; a radio-frequency communication circuit configured to transmitor receive the radio-frequency signals via the antenna; a controlcircuit responsive to the radio-frequency communication circuit; anenclosure configured to house the radio-frequency communication circuitand the control circuit; a conductive yoke attached to the enclosure andconfigured to mount the control device to an electrical wallbox; and aconductive member extending around a rear side of the enclosure betweenopposite sides of the yoke.
 2. The wireless control device of claim 1,further comprising: a user interface configured to receive a user input;and a faceplate defining an elongated opening for receiving the userinterface, the faceplate comprising a conductive element electricallycoupled to the yoke via a single electrical connection when thefaceplate is installed on the wireless control device and the userinterface is received through the elongated opening of the faceplate,the conductive element defining a first slot that is substantially thesame size as and substantially aligned with the opening of thefaceplate; wherein the conductive element is configured to operate as aradiating element of the antenna when the faceplate is installed on thewireless control device.
 3. The wireless control device of claim 2,further comprising: a bezel attached to the yoke, the bezel configuredto provide the user interface through the opening of the faceplate whenthe faceplate is installed on the wireless control device; wherein theantenna comprises a driven element located between the bezel and theyoke, the driven element capacitively coupled to the conductive elementwhen the faceplate is installed on the wireless control device, thedriven element defining a second slot that is substantially the samesize as and substantially aligned with the opening of the faceplate whenthe faceplate is installed on the wireless control device.
 4. Thewireless control device of claim 3, wherein the radio-frequencycommunication circuit is electrically coupled to the driven element viatwo drive points located on opposite sides of the second slot atapproximately the middle of the second slot.
 5. The wireless controldevice of claim 4, wherein the conductive member is electrically coupledto the opposite sides of the yoke adjacent the drive points of thedriven element.
 6. The wireless control device of claim 3, wherein theconductive element is attached to a rear surface of the faceplate. 7.The wireless control device of claim 6, wherein the faceplate comprisesa conductive material on the front surface of the faceplate.
 8. Thewireless control device of claim 3, wherein the conductive elementcomprises a conductive material on the front surface of the faceplate.9. The wireless control device of claim 3, wherein the conductiveelement is located inside of the faceplate.
 10. The wireless controldevice of claim 3, wherein the conductive element is electricallycoupled to the yoke via one of a plurality of screws that attach thebezel to the yoke when the faceplate is installed on the wirelesscontrol device.
 11. The wireless control device of claim 2, wherein theconductive element is configured to operate as a patch antenna when thefaceplate is installed on the wireless control device.
 12. The wirelesscontrol device of claim 1, wherein the antenna comprises a slot antenna.13. The wireless control device of claim 1, wherein the antennacomprises a hybrid slot-patch antenna.
 14. The wireless control deviceof claim 1, wherein the conductive member extends horizontally aroundthe rear surface of the enclosure at the center of the yoke.
 15. Thewireless control device of claim 1, wherein the conductive membercomprises a conductive strap, a conductive label, or a conductive paint.16. The wireless control device of claim 1, wherein the conductivemember is a part of the enclosure.
 17. The wireless control device ofclaim 1, wherein the enclosure is made of a material that is conductive.18. The wireless control device of claim 1, wherein the conductivemember is directly electrically coupled to the opposite sides of theyoke.
 19. The wireless control device of claim 1, wherein the conductivemember is capacitively coupled to the opposite sides of the yoke.